Dear student,
When we talk about matter, we say matter is made up of atom and molecules, elements and compounds. Atom is often called a basic unit of matter but even an atom itself is made up of discrete particles: electrons, protons and neutrons. Protons and neutrons comprise the nucleus of the atom while electrons revolve around the nucleus.
All the space in these atoms and molecules are not continuously filled, it is not indivisible. In fact, there is space in it. Electrons revolve around the nucleus, but all the space around the nucleus is not occupied by electrons. Contrary to it, electrons occupy very little space, leaving vast spaces unoccupied.
So, particulate nature of matter means that all matter is made up of discrete particles.
Regards